End-user data may be stored by various organizations. For example, end-user data can include, but is not limited to, address information, credit card information, photographs, e-mails, healthcare records, financial records, electronic documents, messages such as instant messages, associations with other end-users, and other types of information.
An end-user may request to delete a message, a message thread (including various related messages), or even an entire mailbox (or account). Storage systems typically deal with these message deletions in a variety of ways. For example, some storage systems mark messages as deleted but do not actually delete the messages upon the reception of a deletion request. In this case, the messages marked as deleted are not displayed and/or otherwise provided to an end-user when the end-user requests to view messages in his/her mailbox. Other storage systems can permanently delete a message upon the reception of a deletion request. In this case, the messages are immediately deleted.
Messages can include one or more attachments. Typically, the attachments are larger than messages, and thus, the attachments can be stored in a different data store (e.g., database or storage system) than the messages. In addition, for storage efficiency purposes it is often desirable to store a single copy of an attachment for all of the end-users that are associated with the message (e.g., at least one end-user that sent the message and one end-user that receives the message). However, because multiple users are associated with a single message, deleting an attachment when one user deletes a message may not always be appropriate.
Overall, the examples herein of some prior or related systems and their associated limitations are intended to be illustrative and not exclusive. Upon reading the following, other limitations of existing or prior systems will become apparent to those of skill in the art.